Oxygen jet devices



May 30, 1967 e. H. SMITH ET AL OXYGEN JET DEVICES Filed Dec. 24. 1964 4 Sheets-Sheet, 2

- INVENTORS GEORGE H.5MITH LESLIE C. KUN

ATTORNEY May 30, 1967 G. H. SMITH ET AL UXYGEN JET DEVICES 4 Sheets-Sheet 3 Filed Dec. 24, 1964 m SIN RM 08m m T N. ma w GE n mRL OS A F:.L GLa m May 30, 1967 5. H. SMITH E AL OXYGEN JET DEVICES 4 Sheets-Sheet 4 Filed Dec. 24, 1964 INVENTORS GEORGE H. SMITH LESLIE c. KUN

B ATTORNZ United States Patent 3,322,419 OXYGEN JET DEVICES George H. Smith, New Providence, N.J., and Leslie C. Kun, Williamsville, N.Y., assignors to Union Carbide Corporation, a corporation of New York Filed Dec. 24, 1964, Ser. No. 420,869 1 Claim. (Cl. 266-34) This invention relates to metallurgical lances, and more particularly to oxygen jet devices for use in steelmaking furnaces.

The invention provides fluid jet devices having hollow tips which comprise at least one integral cusp that projects into the space through which cooling liquid flows, for greatly increasing the useful life of the tip by effectively increasing the transfer of heat to such liquid.

More particularly, the invention provides a metallurgical lance comprising, in combination, a hollow tip composed of metal having a lower end wall merging into an integral annular side wall, and a plurality of separate posts having in each an outwardly and downwardly inclined oxygen gas discharge passage, and means for increasing the heat transfer to cooling water through the tip, including a plurality of integral cusps on the inner surface of the end wall and on the back of such posts providing curved water passages therebetween, causing such water to flow with a scrubbing and scouring action as the direction thereof is changed in flowing over the surfaces of such cusps.

The main object of the invention is to increase the useful life of such devices without increasing the cost thereof.

Another object is to provide an oxygen jet device having a tip that has a useful life that is substantially longer than that of those of the prior art.

A still further object is to provide a fluid cooled oxygen lance tip that is simple and economical in construction, requires little machining and can be readily and quickly assembled.

Briefly, such objects are accomplished by the provision of at least one integral cusp on the inner side of the end wall of the water-cooled tip of the device. Such cusp may be in the form of a pyramid located in the center of the tip, and/or substantially transverse vanes, wings or foils located in an annulus around and radially spaced from such center. Each cusp functions not only to increase the effective heat transfer surface area over which the cooling water flows, but more importantly also acts to change the direction of flow of the water, thereby effectively causing a scrubbing and scouring action on the adjacent metal surfaces thereby ever bringing relatively colder water into intimate contact with such surfaces, and thus improving the over-all heat transfer.

According to the invention there is also provided a metallurgical lance comprising, in combination, a hollow tip composed of metal having an end wall merging into an integral annular side wall, and a plurality of posts having in each oxygen gas discharge passage, and means for directing cooling liquid through the tip, including an integral cusp on the downstream side of each post, providing water passages, causing such water to flow with a scrubbing and scouring action as the direction thereof is changed in flowing over the adjacent surfaces of such cusps.

In the drawings:

FIG. 1 is a fragmentary view mainly in vertical section taken on line 11 of FIG. 2 of an oxygen jet device embodying the invention;

FIG. 2 is a horizontal cross section of such device taken on line 22 of FIG. 1;

FIG. 3-is an exploded perspective view of the tip;

FIG. 4 is a perspective view of the external parts of a partially assembled tip;-

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FIG. 5 is a similar view of the internal parts; and

FIG. 6 is a perspective view of the entire tip.

As shown in the drawings, oxygen jet device 10 includes three elongated steel pipes 12, 14 and 16 that are arranged in spaced concentric relation to provide a central supply passage 18 for oxygen, and tubular cooling water inlet and outlet passages 20 and 22. The pipes are about sixty feet long and are connected at their upper ends to a unit casting (not shown) provided with suitable plumbing connections for the oxygen supply, the cooling water supply and discharge. As an example, oxygen supplied to the device in the illustration is about 10-25 thousand cubic feet per minute while about 5-8 hundred gallons per minute of cooling water flows through the device. The device 10 is about ten inches in outside diameter.

The device is provided with a tip 24 that comprises a monolithic casting composed of highly heat conductive metal, such as copper, and alloys thereof, having three inclined pillars or posts 26. Such posts are hollow and arranged in downwardly and outwardly inclined relation between an inner transverse wall or plate 28 and an end or front wall 30. The latter merges into an annular outer side wall 32 the upper rim of which is annularly welded at 33 to the lower rim of a copper collar 32 that is, in turn, welded to a steel collar 16 at 33, the latter being welded to the pipe 16 at 33". The upper rim of the transverse wall 28 is similarly welded at 35 to the lower rim of a copper collar 12 that is, in turn, welded to a steel collar 12" at 35', the latter being welded to pipe 12 at 35", FIG. 1.

Three horizontal plate-segments 36 are mounted on the top of curved flanges or vanes 38 that are integral with the internal surface of end wall 30. Such segments 36 are welded at 40 to the lower rim of a steel collar 14 that is, in turn, welded at 40 to the intermediate pipe 14 in spaced relation to the transverse wall 28. The plate-segments 36 act as cooling water baflies, causing the cooling water to flow first inwardly around the upper portions of posts 26 and then downwardly in the central space therebetween.

A cusp comprising triangular pyramid 42 extends up wardly from the inner surface or floor of the end wall 30 for then directing such downwardly flowing cooling water outwardly toward the lower portions of the posts 26, and into the arcuate ways 44 between the curved vanes 38. Such arcuate ways 44 positively direct the water outwardly, continuously and completely around the entire outer surface of the lower portion of each post. Such water finally flows upwardly through tubular passage 22. Inwardly projecting protrusions 46 on the inner surface of the annular wall 32 are located and shaped so that each cooperates with a cusp 48 extending laterally and downstream from each post 26. Each cusp 48 is in the form of a curved nose or protuberance, as shown.

The pyramid 42, flanges 38, protrusions 46 and noses 48 have important functions that include the following:

(1) Act as momentum changing surfaces to constantly change the momentum of the cooling waterthus ever breaking up and renewing the thermal boundary layer, thus effectively increasing the transfer of heat from metal to flowing water.

(2) Act as constrictors to control the cooling water velocity and maintain it at a high level throughout its flow across the front face.

(3) Act as water diverters to prevent any stagnation from occurring in the flow of cooling water through the critical lower portion of the tip.

(4) Act as extended heat transfer surfaces in critical cooling areas.

As a result of this novel construct-ion, the useful life of the tip in steelmaking furnaces is substantially increased compared to prior devices, since the tip is much more effectively water cooled, especially adjacent critical zones, such as those where the annular inner surface 50 of each oxygen port 52 meets the outer surface 54 of the end wall 30.

In use, the jet device or lance is lowered in the furnace to a level just above the molten steel being made in such furnace and oxygen is discharged downwardly from the ports 52 toward the surface of such molten steel, raising the temperature of the latter by reacting with combustible components of the bath. The cooling water passages in the lower portion of the tip are proportioned and shaped so that water flows through all of them in constantly full, continuous streams, without interruption, and without the formation of any vapor pockets adjacent the smooth surfaces of the metal, which surfaces are streamlined, so that maximum heat is conducted to the water flowing through such passages or ways with a minimum of water pressure loss due to friction. The sum of the benefits provided by the cusps in the tip, increase the effectiveness of the cooling water to such an extent that the useful life of the tip is greatly extended, and this advantage is achieved without increasing the cost of the tip.

While the illustrated example of the invention comprises a casting, the invention is not limited thereto, since the tip may be made of forgings which, in some cases, are better, especially in the case of the tip per se, due to the production of a more uniform product in manufacture. Also, while the example is provided with three posts, any desired or required number of posts may be provided without departing from the invention.

What is claimed is:

A metallurgical lance comprising a tip composed of a metal having an end wall that merges into an annular side wall, and a transverse wall spaced inwardly and upwardly with respect to said end wall and with the inner annular surface of said annular side wall, a plurality of inclined hollow posts connected at one end to said transverse wall and at the other end to said end wall, said posts having oxygen gas outlet passages the longitudinal axes of which are inclined downwardly and outwardly, an inner oxygen supply pipe connected to the upper rim of said transverse wall, an outer pipe connected to the upper rim of the annular side wall of said tip, and an intermediate pipe connected to the tip below and between said other pipes, the annular space between the inner and intermediate pipes providing a tubular cooling water inlet passage, and the annular space between the intermediate and outer pipes providing a tubular water outlet passage, and means for positively directing cooling water circumferentially around the lower portions of said posts, including a plurality of integral cusps on the inner surface of said end wall in the form of a central pyramid, curved vanes radiating therefrom, and a curved protuberance on the downstream side of the lower portion of each post, each cusp functioning not only to change the direction of flow of the water, thereby effectively causing a scrubbing and scouring action on the adjacent metal surfaces, thereby ever-bringing relatively colder water into intimate contact with such surfaces, but also increasing the heat transfer surface area over which the cooling water flows, and thus improving the over-all heat transfer, effectively keeping the tip relatively cool in use, especially at the critical areas including those adjacent the outer face of said end wall.

References Cited UNITED STATES PATENTS 12/1958 Cox.

8/1965 Berry 266-34 

